The nucleus of Arcuatus (extended marrow)

Nucleus arcuatus (medulla oblongata)

The core (sometimes a broken gray string) is located on the front of each pyramid. The Arcuatus nucleus is thought to represent a group of pons nuclei displaced to the front of the pyramid. The nucleus receives signals from the pyramidal path and is connected to the cerebellum via the lower cerebellar arm.

Not to be confused with the nucleus arcuatus of the hypothalamus